P0846

DTC P0846: Clutch 2 Pressure Sensor System (Poor performance)

CAUTION
^ If there is any problem in the CAN bus lines, an incorrect diagnostic trouble code may be set. Prior to this diagnosis, diagnose the CAN bus lines.
^ Whenever the ECU is replaced, ensure that the CAN bus lines are normal.

DIAGNOSTIC FUNCTION
TC-SST-ECU checks that the clutch 2 pressure sensor is normal.

DESCRIPTIONS OF MONITOR METHODS
The difference between the allowable torque of clutch 2 and the engine torque is large.

MONITOR EXECUTION
^ Continuous

MONITOR EXECUTION CONDITIONS (OTHER MONITOR AND SENSOR)

Other Monitor (There is no temporary DTC, stored in memory for the item monitored below)
^ P0847: Clutch 2 pressure sensor system (Output low range out)
^ P0848: Clutch 2 pressure sensor system (Output high range out)
^ P0753: Shift select solenoid 1 system (Open circuit)
^ P0973: Shift select solenoid 1 system (Short to ground)
^ P0974: Shift select solenoid 1 system (Short to power supply)
^ P2809: Clutch/shift switching solenoid 2, spool stuck
^ P2812: Clutch/shift switching solenoid 2 system (Open circuit)
^ P2814: Clutch/shift switching solenoid 2 system (Short to ground)
^ P2815: Clutch/shift switching solenoid 2 system (Short to power supply)
^ P181B: Clutch 1 (Pressure low range out)
^ P181C: Clutch 1 (Pressure high range out)
^ P181E: Clutch 2 (Pressure low range out)
^ P181F: Clutch 2 (Pressure high range out)
^ P185D: Clutch open not possible

Sensor (The sensor below is determined to be normal)
^ Shift select solenoid 1
^ Clutch/shift switching solenoid 2

LOGIC FLOW CHARTS (Monitor Sequence)





DTC SET CONDITIONS

Check Conditions
^ Voltage of battery: 8 V or more.
^ Voltage of battery: 16.5 V or less.
^ Engine speed: 650 r/min or more.
^ Time since above engine condition: 1.5 seconds or more.
^ Engine speed: 6,800 r/min or less.
^ Clutch 2 (even) slip state: Slip or engaged.
^ Clutch 2 (even) slip speed: 20 r/min or more.
^ Clutch 1 (odd) state: Disengaged.

JUDGMENT CRITERIA
^ Calculated torque (Clutch 2 (even) permit torque engine torque): 200 Nm (148 ft-lb) or more. (4 seconds)

OBD-II DRIVE CYCLE PATTERN
The value of the calculated torque (clutch 2 (even) permit torque engine torque) remains 200 Nm (148 ft-lb) or less for 4 seconds.

PROBABLE CAUSES
^ Malfunction of TC-SST-ECU
^ Malfunction of clutch 2 pressure sensor
^ Malfunction of clutch assembly
^ Malfunction of engine system
^ Insufficient fluid

DIAGNOSTIC PROCEDURE

Required Special Tools:
^ MB991958: Scan Tool (M.U.T.-III Sub Assembly)
^ MB991824: Vehicle Communication Interface (V.C.I.)
^ MB991827: M.U.T.-III USB Cable
^ MB991910: M.U.T.-III Main Harness A

STEP 1. Scan tool CAN bus diagnostics
Using scan tool MB991958, diagnose the CAN bus lines.
Q: Is the check result normal?
YES: Go to Step 2.
NO: Repair the CAN bus lines. After repairing the CAN bus line, go to Step 2.

STEP 2. Scan tool diagnostic trouble code
Check the engine diagnostic trouble code. Diagnostic Trouble Code Descriptions
Q: Is the DTC set?
YES: Perform the relevant troubleshooting.
NO: Go to Step 3.

STEP 3. Fluid check
Drain the fluid and check that no bubbles, foreign material and contamination are found.
Q: Is the check result normal?
YES: Go to Step 4.
NO: Replace the fluid.

STEP 4. Check whether the DTC is reset.
1) Erase the DTC.
2) Gradually accelerate the vehicle.
3) Accelerate the vehicle with the accelerator pedal fully opened.
4) Check that the DTC is reset.
Q: Is DTC No. P0846 set?
YES: Replace the clutch assembly.
NO: Intermittent malfunction.